According to their own properties, plastics can be divided into two categories: thermoplastics that can be repeatedly processed by melting and forming, and basically retain their properties, and thermosetting plastics that can only be melted at one time. Points can be divided into wide use, according to the use of cheap, common plastics, good comprehensive properties such as PE, PP, PVC, PS, has good physical and mechanical strength and amino plastics, can use plastic instead of metal engineering in construction machinery such as: ABS, nylon, polyester, POM. TPX-1. As well as a kind of engineering plastics with excellent performance on some properties, for example: special plastics with excellent radiation resistance and high temperature resistance, such as polysulfone, liquid crystalline polymer and so on. According to the crystalline size of the thermoplastic resin, the thermoplastic plastics can be divided into two types of amorphous and crystalline polymers.